[benj111]

>It should be looked form the frame of how long is appropriate to promote the creation of the arts etc

I agree, I don't see how 20 years isn't long enough from that pov.

What company is going to wait 20 years before signing a book deal, film deal, etc.

Further. This still ignores the fact that there's value to having the original creator attached. You don't want the author of the book trashing your new film, you want them promoting it.